Some DMA engines and peripherals require that buffers are precisely
aligned. This commit marks BBBuffer as #[repr(C)] so that the buffer is
the first member of the struct. With this guarantee, we can align the
BBBuffer for our hardware-assisted transfers. Updated documentation
shows one way to align the buffer.
Tested on an i.MX RT processor, where the DMA engine requires circular
buffers that are power-of-two sized and aligned. If I can't align my
BBBuffer, I'll treat the BBBuffer as linear memory and schedule multiple
transfers to handle split_read wraparound. I'm happy to go this route if
this commit isn't appropriate for bbqueue.
Some DMA engines and peripherals require that buffers are precisely aligned. This commit marks BBBuffer as #[repr(C)] so that the buffer is the first member of the struct. With this guarantee, we can align the BBBuffer for our hardware-assisted transfers. Updated documentation shows one way to align the buffer.
Tested on an i.MX RT processor, where the DMA engine requires circular buffers that are power-of-two sized and aligned. If I can't align my BBBuffer, I'll treat the BBBuffer as linear memory and schedule multiple transfers to handle split_read wraparound. I'm happy to go this route if this commit isn't appropriate for bbqueue.